But he could wait until as late as tomorrow afternoon before making his decision known to Kasper Schmeichel and Shane Higgs.
Grayson said: "Both of them have performed really well in pre-season and one of them is going to be disappointed. I've got an idea of who I'm going to use.
"Sometimes I name my team at half past one on a Saturday and sometimes I name it (earlier). I've not decided when I'll tell them.
"But whoever gets left out will be very unfortunate. You can only pick 11 players and the team that starts the season isn't always the team that plays the majority of the games.
"My advice to whoever isn't in the team will be to get their head down and work hard."
Grayson said: "Both of them have performed really well in pre-season and one of them is going to be disappointed. I've got an idea of who I'm going to use.
"Sometimes I name my team at half past one on a Saturday and sometimes I name it (earlier). I've not decided when I'll tell them.
"But whoever gets left out will be very unfortunate. You can only pick 11 players and the team that starts the season isn't always the team that plays the majority of the games.
"My advice to whoever isn't in the team will be to get their head down and work hard."